In addition to considering the GCS, severity of brain injury is further based on Post-Traumatic Amnesia (PTA) Duration (Bigler, as cited in Lezak, 1995). Post-traumatic amnesia, or the period of time until continuous memory is established is another simple method of classifying severity of head injury.

PTA Duration…………Severity of Injury

< 5 minutes…………..Very mild

5 – 60 minutes………..Mild

1 – 24 hours………….Moderate

1 – 7 days……………Severe

1 – 4 weeks…………..Very severe

4 weeks…………….Extremely severe

Mild Traumatic Brain Injuries (mTBI)

Mild Traumatic Brain Injury (mTBI) plays murky second-fiddle to its notorious sisters: Moderate and Severe TBI. Its etiology is ambiguous, attempts at assessment often equivocal, and predictions of recovery problematical. This does not, however, mitigate its enormous impact on patients and their families. The reality is, a great number of Traumatic Brain Injuries fall into this nebulous “mild” category, and an even greater number of these go undiagnosed.

Why does this happen? For one thing, the symptoms of this neurological disorder don’t always materialize until weeks or months after the causal incident. Initial diagnosis, often in the Emergency Room immediately following the event, often doesn’t catch the more pervasive symptoms that can occur. For example, MTBIs are almost always more symptomatic twenty-four hours post-incident then they are within the first couple of hours. Symptoms escalate over this twenty-four hour period because MTBI involves a cascade of neurometabolic events in the brain, characterized by a stepwise process of ionic shifts, altered brain metabolism, impaired neuronal connectivity and disruption of normal neurotransmission. Translation: these changes and their corresponding symptoms take time to manifest.

Another confounding factor is that many of the symptoms of MTBI are also common symptoms of other health problems. Cognitive symptoms include problems with attention, concentration, orientation, and memory. Physical symptoms include headaches, dizziness, insomnia, uneven gait, nausea, and blurred vision. Behavioral changes include irritability, depression and anxiety. You could suffer from a Mild Traumatic Brain Injury and experience only one of these symptoms. Brains are extremely complex systems and each one reacts differently to change.

In addition to brain complexity there is incident complexity: the multitude of ways to incur an MTBI. They run the gamut from getting hit on the head by a baseball bat, a bad football tackle, to getting into a car accident. Or, for our veterans out there, being near the impact zone of an explosion. There doesn’t have to be a direct blow to the head to sustain such an injury. They can also form internally, inside our brains, through violent movement of the skull and its fragile contents.

For example, consider the whiplash effect caused by even a small car accident. It starts a chain reaction inside your head. The brain is made up of millions of nerve cells connected by fibers called axons. When the head is thrust from side to side and front to back, some axons, which carry messages between brain cells, get torn or twisted. This wide range of causation makes it increasingly difficult to predict MTBI outcomes for individual patients.

How do we delineate between MTBI and its big sisters? One way lies in the severity of the injury itself (see above for explanation of classification). For example: all Traumatic Brain Injury subtypes involve Post-Traumatic Amnesia (loss of memory), an alteration of consciousness, an alteration of mental state, and neurologic deficits (that generally appear using neuroimaging like MRI or CT). Mild Traumatic Brain Injury is characterized by an alteration of consciousness of less than thirty minutes, a memory disturbance of less than twenty-four hours, focal neurologic deficits (that may or may not show up through neuroimaging) and a Glasgow Coma Scale score of at least thirteen. To complicate diagnostic efforts further, MTBI can occur without any loss of consciousness at all.

There are other non-disease related issues that also confound MTBI diagnosis. Consciousness and memory can be affected by any medications the patient was taking before the incident, in addition to those given at the scene. Another important factor is the potential reluctance of each patient to be fully honest about his or her symptoms. Let’s face it: no one wants to admit that they might have a neurological disorder when it’s so easy to find a million other factors to blame their symptoms on. For a disorder that is so dependent on the analysis of cumulative symptoms for diagnosis and treatment, willful blindness on the part of patients becomes a huge confounding factor. Just in case that wasn’t complicated enough, for those patients that want to get to the truth behind their symptoms, depending on the location and nature of each injury, the symptoms can confound their own diagnosis. For example, if you experience changes in cognition, this will alter your awareness and judgment and impair your ability to recognize and report your symptoms. It’s a vicious circle.

As mentioned above, one of the major differences between Mild TBI and Moderate and Severe TBI is that the diagnosis, treatment and recovery of MTBI is more dependent on the individual patient’s symptoms and non-injury related issues; whereas for Moderate and Severe TBI, these aspects are more directly correlated with the mechanics of the injury (meaning the location and severity of the actual hole in the head dictates prognosis). Predictors of recovery for Mild Traumatic Brain Injury include the patient’s psychological and socioeconomic issues, post-injury stressors, alcohol and drug problems and litigation factors.

Patients dealing with MTBI often experience fear of being seen differently due to their disorder. They don’t want to be viewed by themselves or others as “damaged.” They attempt to hide their symptoms and have difficulty accepting a change in their ability to live independent lives, no matter how temporary. The anger, depression and social anxiety that may occur due to their experience makes it even more difficult to accurately treat them. All of these behaviors can lead to physical and emotional isolation. This communication gap then causes a rift between the patient and their support system. It’s incredibly important for not only the patients to be well educated about what to expect, but that their families are also involved in the diagnosis and recovery process.

Things to watch out for post-incident: Post-Concussive Syndrome and Second Impact Syndrome. Post-Concussive Syndrome occurs when the symptoms last for weeks, months or years following the causal incident. If you incur another MTBI before you’ve recovered from symptoms of the first, Second Impact Syndrome can occur. This syndrome is characterized by a rapid swelling of the brain. This dangerous development is most likely to happen to athletes that return to their sport too soon and soldiers that return to battle too soon. Recurrent MTBI may be associated with longer recovery time and long-term risk of psychiatric and neurological dysfunction. Two of the more common cumulative effects are psychiatric disorders and loss of long-term memory. For example, retired football players with a history of three or more concussions have a higher risk of developing clinical depression than those with no concussion history.

Is there a silver lining to be found here? Yes! Most patients suffering from Mild Traumatic Brain Injury return to their normal level of function within a few weeks to a few months of the incident. It is much more rare to have long-term complications. Additionally, testing techniques are improving as researchers get a better handle on how best to go about diagnosis and treatment.

Because of MTBI’s dual neurological and psychological forces, it is most beneficial to clinicians and patients to approach the disorder as a neuropsychological construct. It is a neurological injury by form and function, but psychological factors have a large impact on the treatment and long-term outcome of the disease. Because of this, neuropsychologists, who address this overlap between neurology and psychology are by nature best qualified to deal with all aspects of disease diagnosis and management.

What does all this tech-speak translate to in reality? The best way to determine your fitness after your incident is to trust yourself and your knowledge of your body. Keep careful tabs on yourself to see what changes have occurred pre- and post- incident. Do you have difficulty remembering things? Is your vision blurry and depth perception off? Have you had noticeable changes in energy level and mood? Do you have a diminished reaction time? These are all key clues to report to your doctor immediately. If you are one of those that experience long-term effects, seek help. There are doctors out there that specialize in TBI rehabilitation.

Mild Traumatic Brain Injury has become a commonly misdiagnosed and misunderstood public health problem. The multitude of ways this type of brain injury can be formed makes it hard for doctors to map the causative event and make predictions for diagnosis and recovery. The fact that it has to be approached quite differently than its other TBI counterparts further confounds efforts toward accurate diagnosis and care. In order for an effective prognosis to be formed for a patient, a combination of factors must be assessed: the biomechanics of the incident, presence of neurologic deficits, reported symptoms, patient’s medical history, and post-injury psychosocial issues. While increased sensitivity in neuroimaging techniques and neuropsychological testing will hopefully lead to a more fine-tuned diagnosis, it is crucial that each individual patient take responsibility for their own symptoms and progress. It is only through the combined efforts of doctors, patients and their families that positive outcomes for this potentially debilitating disorder can be reached.